10-28-2025
07:54 PM
- last edited on
10-28-2025
10:39 PM
by
Tiffany
I'm just a little confused. I have a beginner Canon EOS R100 and have purchased a new lens 100-400 and works fine. I first started with a used 75-300 EF mount with an adapter, then purchased used EF teleconverter so I got 150-600. I wanted to change everything to all RF mount lenses so I purchased the RF mount 100-400 lens. I was a little upset that the extender 2.0 was so expensive (more than the 100-400 lens that I purchased). I made sure the 100-400 lens was compatible with the rf 2x extender but now I've read somewhere the extender is not compatible with my camera EOS R100. It fits fine on my camera but I just want to make sure I'm not messing the camera up. I do want to eventually purchase a nicer camera (EOS R7). This bird watching hobby I started is quite expensive. Is it ok to use the extender on my camera without messing it up? I don't understand how it could not be compatible if it goes right on my camera no problem
Solved! Go to Solution.
10-28-2025 09:31 PM
Teleconverters are NOT COMPATIBLE with the EOS R100. The problem is the older hardware in the camera body. Not the camera’s physical lens mount. Or the lens being used. I would avoid using teleconverters on your camera. Even though it may mount it’s not a compatible combination. It may or may not cause damage to your camera.
10-29-2025 01:41 AM
JENDUPLANTIS,
In reading through various Internet postings in different forums, it looks like your R7 would be compatible with a 2X extender - some posters actually speak of their experience using one' and as Demetrius said, the RF system, as a whole is compatible.
The only incompatibility appears to lie with the lenses.
From Canon's website on the RF 2X extender compatibility page:
RF400mm F2.8 L IS USM
RF600mm F4 L IS USM
RF600mm F11 IS STM
RF800mm F5.6 L IS USM
RF800mm F11 IS STM
RF1200mm F8 L IS USM
RF70-200mm F2.8 L IS USM Z
RF100-300mm F2.8 L IS USM
RF100-400mm F5.6-8 IS USM
RF100-500mm F4.5-7.1 L IS USM
RF200-800mm F6.3-9 IS USM
Steve Thomas
10-28-2025 09:31 PM
Teleconverters are NOT COMPATIBLE with the EOS R100. The problem is the older hardware in the camera body. Not the camera’s physical lens mount. Or the lens being used. I would avoid using teleconverters on your camera. Even though it may mount it’s not a compatible combination. It may or may not cause damage to your camera.
10-28-2025 09:44 PM
JENDUPLANTIS,
I was going to give you the same information that Demetrius did.
You can read this in a Canon website called Supplementary Information for the R100
https://cam.start.canon/en/H001/supplement_0170.html
Steve Thomas
10-28-2025 10:09 PM
Thank you. How can I find the compatibility guide for the Canon EOS R7 which is the camera I want to upgrade to. Hoping the RF 2x extender is compatible with it and my 100-400 lens. I thought I was going to be able to use my R100 until I could upgrade the camera. I think I had a better set up with the used ef mount 75-300 with adapter and 2x teleconverter than i do now with the rf mount 100-400 for capturing birds in flight at a longer distance.
10-28-2025 10:16 PM
Other RF Mount cameras are compatible with teleconverters. A long with lenses that support them. The official Canon teleconverters is NOT COMPATIBLE with the EF 75-300mm lens by design. Canon’s teleconverters protrude into the lens. Thus making that lens incompatible with official Canon brand teleconverters.
10-28-2025 10:33 PM
I know the canon RF teleconverter is not compatible with the EF 75-300. My question was where do I find the compatiblilty guide for the Canon EOS R7 to make sure it is compatible with this almost $700 RF 2x extender I just purchased. I was using the EF 75-300 with an adapter and a differernt teleconverter on my EOS R100 when I decided to upgrade to an RF 100-400 lens but just found out I cannot use this RF 2x extender with my current camera (EOS R100). I want to upgrade my camera
10-28-2025 10:44 PM
All RF Mount cameras are compatible with teleconverters. Excluding the EOS R100. The EF 75-300mm is NOT COMPATIBLE with official Canon brand EF Mount teleconverters.
10-28-2025 11:05 PM
Thank you. I guess I just have the only RF camera that is not compatible. It is a beginner camera for me. I guess it's time to upgrade!
10-29-2025 01:41 AM
JENDUPLANTIS,
In reading through various Internet postings in different forums, it looks like your R7 would be compatible with a 2X extender - some posters actually speak of their experience using one' and as Demetrius said, the RF system, as a whole is compatible.
The only incompatibility appears to lie with the lenses.
From Canon's website on the RF 2X extender compatibility page:
RF400mm F2.8 L IS USM
RF600mm F4 L IS USM
RF600mm F11 IS STM
RF800mm F5.6 L IS USM
RF800mm F11 IS STM
RF1200mm F8 L IS USM
RF70-200mm F2.8 L IS USM Z
RF100-300mm F2.8 L IS USM
RF100-400mm F5.6-8 IS USM
RF100-500mm F4.5-7.1 L IS USM
RF200-800mm F6.3-9 IS USM
Steve Thomas
10-29-2025 06:02 AM
Do you know what the actual incompatibility is?
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